What products are involved?
Rheonics Density and Viscosity meter SRD
What is the purpose of this article?
To give an overview of the Reactor Probe (-RP) version, -X7 configuration, of the SRD sensor and installation information.
1. Overview
The Rheonics Reactor Probe (RP) design for the SRD is a long insertion probe with a 19mm body diameter, configurable by total “L” length and flexible (adjustable) process connection, with PTFE-PEEK or Stainless Steel 316L compression fittings. Its order code is -X7.
The Rheonics SRD is an industrial sensor used to measure with high accuracy the density and viscosity of a fluid inline, to enable monitoring and control. Rheonics offers different variants for the SRD to adjust the sensor probe to the user’s needs and application requirements, see more here.
The SRD-X7 variant is suited for installations in bioreactor tanks and glass reactors using a long insertion probe with compression fittings of 1” NPT, 3/4” NPT and others in two material options PTFE and Stainless Steel.
PTFE-PEEK fittings allow a variable insertion length (distance from fitting to sensor tip) since the fitting can be moved along the shaft of the probe. Stainless Steel compression fittings are generally fixed in a position once they are compressed.
The SRD Reactor Probe is defined by the total length, there are 4 options available: 150, 250, 350 and 450mm. The client can also define the compression fitting required that will be placed at some point along the shaft once received. The probe can be ordered without a compression fitting as well.
Figure 1: Reactor Probe Density and Viscosity Meter with 3/4" NPT PTFE Compression Fitting.
Figure 2: SRD-X7 Reactor Probe Dimensions mm [in.]
| Specifications | |
| Sensor compatibility | |
Order code | SRD-X7-RPyyy-Bzzz |
Total length L - yyy | 150, 250, 350 and 450 mm |
Connection type B - zzz | Customizable (min. OD 22mm) |
Drawings | SR-RP Configuration Drawing |
SRD-RP CAD files | ||
Sensor Variant | Drawing | CAD File |
SRD-X7-RP150 | ||
SRD-X7-RP250 | ||
SRD-X7-RP350 | ||
SRD-X7-RP450 | ||
Some installation possibilities for the SRD Reactor Probe are:
- Installation in reactors, in particular bioreactors
- Installations with variable insertion length
- Installation in small pipe sizes (e.g. 1”, 1.25” ID pipes)
- Installation in pipe sizes bigger than 1.5” with reduced (compared to -X5 sensors) cross section reduction inside the pipe due to probe.
Figure 3: SRD-X7 Reactor Probe comparison with SRD-X5.
2. Installation principles
The Rheonics SRD-X7 can be easily installed and integrated into an existing setup. Next considerations should be followed to ensure accurate, repeatable and reproducible density and viscosity readings.
Figure 4: SRD-X7 Reactor Probe sensing element.
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Tank or vessel installation with mixing fluids can add high noise to the readings of the SRD. For mixing processes, unless the mixing is slow and at a constant speed, recomendation is to install the SRD in recirculation lines, which offer a better defined flow around the sensing element. Visit this article on comparisons between installation in tank and recirculation line.3. Fitting options
A compression fitting is a mechanical device used to create a sealed connection between two pieces (e.g. pipes) without conventional methods like welding or heating. The sealing is achieved thanks to compression forces between its inner parts. These are the Compression Nut, Back Ferrule, Front Ferrule and Fitting Body. The later is connected to the process by a custom connection.
Figure 5: Compression Fitting parts
Compression fittings are offered with the Rheonics SRD Reactor probe to be used as non-welded process connection with variable insertion length. The insertion length is defined as the distance between the sensor probe tip to the process connection. Next Figure shows how the back or rear ferrule is deformed due to compression against the sensor body once the nut is threaded in the fitting or connector body. Depending on the back ferrule material, the deformation is momentary and exist only when is compressed (PTFE-PEEK) or permanent so it stays deformed and fixed even if compression nut is unthreaded (Stainless Steel).
Figure 6: Rheonics RP Compression Fitting Cross Section View
3.1 PTFE-PEEK Compression Fittings
As mentioned above, PTFE compression fittings can be moved along the sensor probe shaft and be compressed at different points each time it is installed, deformation is not permanent.
This fitting is made of PTFE and includes a PEEK olive back ferrule for a secure grip. These have an excellent chemical and temperature resistance and reduce the contamination and requirement for cleaning.
See how to install the PTFE-PEEK compression fitting here
Figure 7: PTFE-PEEK Compression Fittings. Source: Avantor
3.2 Stainless Steel Compression Fittings
These fittings have all inner parts (connector, nut and ferrules - back and front) made of Stainless Steel SS316L. This offer a higher pressure rating. The ferrules get deformed when nut is tightened the first time, creating a mechanical bond with the probe shaft. This has the advantage of defining a fixed position for thread engagement but also means that user can’t vary the compression point after first installation.
See how to install the Stainless steel compression fitting here
Figure 8: STainless Steel Compression Fitting. Source: Swagelok
4.Configuration examples
Next there are some possible configurations for the SRD-RP and its order codes.
3/4” NPT Thread: This is the SRD reactor probe variant with a 3/4” NPT compression fitting in PTFE or SS316L material. Rheonics offers this connection welded in its standard short sensor SRD-X1. The advantage the -RP Type sensor offers is the longer insertion of the probe as shown in next two figures for a 150 and 250 L variant.
Figure 9: SRD-RP150-B34N
Figure 10: SRD-RP250-B34N
SRD-RP L: 250 mm B: 3/4” NPT | |
Part | Order Code |
SRD-RP Reactor Probe Density and Viscosity meter | SRD-RP250-B34N |
1” NPT: Compression fitting is also available with 1” NPT connection for Stainless Steel and PTFE-PEEK variants.
Figure 11: SRD-RP250-B11N
SRD-RP L: 250 mm B: 1” NPT | |
Part | Order Code |
SRD-RP Reactor Probe Density and Viscosity meter | SRD-RP250-B11N |
5. How to order the Rheonics Reactor Probe?
Rheonics SRD-X7 Reactor Probe follows next code form.
How to Order Rheonics long insertion viscometer and density meter | |||
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1 | Rheonics SR-Type sensor SRD: Inline Density and Viscosity meter SRV: Inline Viscometer | 3 | Reactor Probe RP- Length Length from sensor probe back end to tip. Rheonics offers 4 variants:
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2 | Process Connection Configuration X7: Reactor Probe - RP. Probe variant with ∅19 mm body. | 4 | Process Connection "B" Compression fittings defined by client. Common variants are: 3/4” NPT, 1” NPT in Stainless Steel (-S) and PTFE-PEEK (-P). Ask Rheonics Sales Team for availability of other connections.
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The appropriate RFQ page for SRD density and viscosity meter should be used to configure other options of the sensor, like density and viscosity range, calibration accuracy, pressure rating, etc. | |||